Muni's new trains: Good news and bad news

Chuck Finnie, OF THE EXAMINER STAFF

Published 4:00 am, Friday, November 7, 1997

1997-11-07 04:00:00 PDT SAN FRANCISCO -- A new report contains good news for residents bothered by vibration caused by Muni's new Italian-made trains, but concludes that the screeching in the vehicles' motors probably can't be quieted.

Vibration and noise complaints clouded the January debut of Muni's sleek new line of light-rail cars, which thus far have cost the agency $188 million. Municipal Railway officials have been looking for solutions ever since.

"It appears we will be able to mitigate these vibrational issues," said Elaine Cartwright, a Municipal Railway senior project manager.

"As for noise," she said, "it appears we have done as much as we can. It looks pretty bleak."

Muni had only a 10-page executive summary of the study as of Thursday and declined to release the document. As described by Cartwright, however, the report, prepared by an Oakland vibration and noise consultant, supports Mayor Brown's sober assessment of last week.

Brown said the train noise was a fact of life San Franciscans would have to learn to live with.

"It is just a different sound than people are used to hearing," Brown said. "It is just a sound they will have to get used to."

Muni sought the $100,000 study from consultant Wilson, Ihrig & Associates Inc. as the centerpiece of a final set of recommendations to The City's Public Transportation Commission. The panel meets Nov. 18 and wanted answers to vibration and noise problems before placing a new order for 59 more of the cars from manufacturer Breda Construzione Ferroviarie of Italy.

Earlier this year, Muni achieved a modest reduction in the screeching by making adjustments to the motors. But the new report says that approach to muffling noise is exhausted and no other solutions are on the horizon.

Complaints of vibrations have been clustered in three areas of The City.

Along the N-Judah line, at Carl and Cole streets, a substandard soil bed is to blame, according to the study, and a floating slab under the track should do the trick.

Complaints of vibrations in the vicinity of 22nd Street along the J-Church are a misnomer, the report concludes. Instead, the new, heavier Bredas thud as they hit an old track switch - and the report recommends replacing the mechanism.

A third center of vibration complaints, along the L-Taraval line, near 35th Avenue, may be more difficult to address.

Sandy soil in the Sunset District is a conduit for vibration, Cartwright said. The report theorizes that changing the way tracks are embedded and redistributing the weight of the Breda vehicles could produce results.

The proposals are speculative, based on mathematical modeling, and require testing with real-world prototypes.

Thus far, The City has purchased the cars for $2.2 million each, and Muni is slowly introducing the Bredas to its 73 miles of subway tunnels and surface-street rails as drivers are trained to operate them.

No cost estimates of the track work and possible vehicle modifications were available from Muni Thursday.&lt;